The expanding universe

It is Monday morning and I feel miserable like the rest of you, so I’d like to share a few random thoughts on the creation of the universe and how Einstein was wrong.

Einstein assumed like Newton did before him that the universe was static- that it did not move or expand. To account for this, after developing the general theory of relativity, he introduced a “cosmological constant” to his field equations.

Of course Einstein changed his mind and agreed the universe was expanding after Hubble’s astronomical experiments. He got rid of the “cosmological constant”.

But “expanding” is a terrible way to put it because you immediately follow up with the question- what is the infinite universe expanding into?

“Stretching” is a better word. The universe is stretching like a rubber band. Gravity would predict that the stretching of the universe would slow down, but it is actually speeding up! And like a rubber band, the universe might actually snap from stretching.

(No one knows for sure if and when this will happen).

Up until the mid-90s the consensus was that the stretching of the universe was slowing down due to gravitational potential energy of stars and galaxies would finally exceed the kinetic energy of expansion. You could extrapolate this back to a rapid collapse- the Big Crunch- when everything would fall back into a heap. But this isn’t happening- the universe is stretching, not falling.

For the longest time, people felt that dark matter alone (created during the Big Bang) provided the extra gravitational pull to keep the galaxies together. But it isn’t.

The current theory is that there is a “repulsive” or opposite gravitational force called dark energy that has outbalanced true gravity for the last 6 billion years. So though Einstein was wrong, we need his cosmological constant to balance the equation against gravity. But no one really knows why the universe is expanding faster.

Regarding the creation of the universe, scientists can’t get to the Big Bang but can extrapolate to tantalizing close- to less than a microsecond of when it happened! Note that the Big Bang Theory doesn’t actually say what banged or why it banged.

But what happened before the first microsecond is mysterious to everyone. No one knows how the universe was actually created.